The claimed inventions relate to injection control methods of an injection molding machine, specifically to a programming method for setting input data by using functions for defining injection speed and pressure control pattern profiles in order that a plurality of kinds of mold products are molded under an appropriate programmed injection control in a single injection molding machine.
In an injection molding machine, injection control conditions are generally determined in accordance with a predetermined control pattern profile. Namely, as shown in FIG. 3 to FIG. 5, injection speed VI of a filling process and holding pressure P of a pressure holding process are set in accordance with each control pattern profile on the predetermined number of steps.
In each figure there are 10 steps on injection speed necessary for operating one filling process, each step corresponding to the block VI 1 to the block VI 10 as shown in areas under the rectangle wave form in accordance with the stroke position in the process.
Also, there are 4 steps on holding pressure necessary for operating one pressure holding process, each step corresponding to the block PH1 to the block PH4 as shown in areas above the rectangle wave form in accordance with the time in the process.
As to the injection speed VI, there are 3 shape modes, that is, the rectangle mode, the slope mode and the polygonal line mode. The rectangle mode is shown in FIG. 3 as the rectangle wave, the slope mode is shown in FIG. 4 as the slope wave, and the polygonal line mode is shown in FIG. 5 as the polygonal line wave.
As to the holding pressure P, only the rectangle mode is defined as shown in FIG. 3 to FIG. 5.
Therefore, it is possible to improve the quality of mold products to an extent by selecting an appropriate one of the modes in view of the product characteristics in molding and setting data for injection control operation under the selected mode.
However, there exist problems to be solved in setting injection control program data mentioned above.
Namely, in the above conventional method of setting, because of conventional control system configuration, the numbers of speed or pressure changing steps in a filling process or pressure holding process are also limited to only 10 steps or 4 steps, respectively, and the numbers of shape modes are limited to three, that is, the rectangle, the slope and the polygonal line. However, much more steps and variety of shape modes are required in order to set a precise and fine injection control program.
In part, the claimed inventions provide methods for setting injection control programs in which an operator is enabled to achieve input operations necessary for operating the filling and pressure holding processes without considering limitations in the numbers of steps.
The inventions also provide methods for setting injection control programs in which an operator is enabled to easily achieve input operations necessary for operating the filling and pressure holding processes by making use of a code corresponding to an input command data.
The inventions also provide methods for setting injection control programs in which an operator is enabled to use a plurality of shape modes even in one filling process or in one pressure holding process.
The inventions also provide methods for setting injection control programs in which an operator is enabled to easily modify injection control conditions already set for other mold products to improve quality and accuracy thereof.
More specifically, there is provided a method for setting an injection speed control pattern profile into a memory of a control apparatus of an injection molding machine, in which a series of stroke position command data necessary for operating one injection filling process are stored together with injection speed command data corresponding to each position, and a plurality of functions for producing each injection speed command data are also stored, the control apparatus controlling actual filling operations by reading out the stored data in the memory, the method includes the following steps of designating a plurality of co-ordinate points on a plane with co-ordinate axes of an injection stroke position and an injection speed, respectively, each as a point on the injection speed control pattern profile, defining a function suitable to a line connecting between two designated and adjacent points, such as a definite straight line or a sectional curve, the connecting line forming a portion of the pattern profile, defining the function as a function to produce the injection speed command data corresponding to injection stroke positions, calculating a plurality of injection speed command data corresponding to each the stroke position between the two designated points by using the function, and storing the calculated data in a first area of the memory.
The co-ordinate points in the designating step are constituted by a code data defined with a code name and its values corresponding to each co-ordinate axis, and the code data are stored in a second area of the memory.
Of course, the co-ordinate points can be directly input on the screen of pattern display in the control apparatus.
The sectional curve in the defining step may be an arc.
There is also provided a method for setting a holding pressure control pattern profile into a memory of a control apparatus of an injection molding machine, in which a series of time command data necessary for operating one pressure holding process are stored together with holding pressure command data corresponding to each time, and a plurality of functions for producing each holding pressure command data are also stored, the control apparatus controlling actual pressure holding operations by reading out the stored data in the memory, the method includes the following steps of designating a plurality of co-ordinate points on a plane with co-ordinate axes of the time and the holding pressure, respectively, each as a point on holding pressure control pattern profile, defining a function suitable to a line connecting between two designated and adjacent points, such as a definite straight line or a sectional curve, the connecting line forming a portion of the pattern profile, defining the function as a function to produce the holding pressure command data corresponding to each the time between the designated two points, calculating a plurality of holding pressure command data corresponding to each time by using the function and storing the calculated data in the first area of the memory.
The co-ordinate points in the designating step are constituted by a code data defined with a code name and its values corresponding to each co-ordinate axis, and the code data are stored in the second area of the memory.
Of course, the co-ordinate points can be directly input on the screen of pattern display in the control apparatus.
The sectional curve in the defining step may be an arc.